From: Marco Elver <elver@google.com>
To: Hillf Danton <hdanton@sina.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>, Jann Horn <jannh@google.com>,
Mark Rutland <mark.rutland@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
kasan-dev <kasan-dev@googlegroups.com>
Subject: Re: [PATCH 1/3] kfence: await for allocation using wait_event
Date: Mon, 19 Apr 2021 11:44:09 +0200 [thread overview]
Message-ID: <CANpmjNMR-DPj=0mQMevyEQ7k3RJh0eq_nkt9M6kLvwC-abr_SQ@mail.gmail.com> (raw)
In-Reply-To: <20210419094044.311-1-hdanton@sina.com>
On Mon, 19 Apr 2021 at 11:41, Hillf Danton <hdanton@sina.com> wrote:
>
> On Mon, 19 Apr 2021 10:50:25 Marco Elver wrote:
> > +
> > + WRITE_ONCE(kfence_timer_waiting, true);
> > + smp_mb(); /* See comment in __kfence_alloc(). */
>
> This is not needed given task state change in wait_event().
Yes it is. We want to avoid the unconditional irq_work in
__kfence_alloc(). When the system is under load doing frequent
allocations, at least in my tests this avoids the irq_work almost
always. Without the irq_work you'd be correct of course.
> > + wait_event_timeout(allocation_wait, atomic_read(&kfence_allocation_gate), HZ);
> > + smp_store_release(&kfence_timer_waiting, false); /* Order after wait_event(). */
> > +
next prev parent reply other threads:[~2021-04-19 9:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 8:50 [PATCH 0/3] kfence: optimize timer scheduling Marco Elver
2021-04-19 8:50 ` [PATCH 1/3] kfence: await for allocation using wait_event Marco Elver
2021-04-19 9:40 ` Hillf Danton
2021-04-19 9:44 ` Marco Elver [this message]
2021-04-19 9:49 ` Marco Elver
2021-04-21 9:11 ` Hillf Danton
2021-04-21 10:27 ` Marco Elver
2021-04-19 8:50 ` [PATCH 2/3] kfence: maximize allocation wait timeout duration Marco Elver
2021-04-19 8:50 ` [PATCH 3/3] kfence: use power-efficient work queue to run delayed work Marco Elver
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